Bunk bed



FIG. 1 is a front, top and left side perspective view of a bunk bed, showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is an enlarged view of a portion of the bunk bed marked in FIG. 1 .

The broken lines in FIG. 1 demarcate enlarged areas and form no part of the claimed design. 

CLAIM The ornamental design for a bunk bed, as shown and described. 